Flow analysis system (FIA, for example) is an analytical procedure capable of performing real-time, on-site analysis. In particular, such procedures are effective for on-site analyses for trace elements contained as impurities in chemicals in a process for fabricating semiconductors where such chemicals are used in extremely high purities. To briefly explain FIA here, it is a type of flow analysis in which a carrier (sample-carrying fluid) is flowed through a flow path, the carrier being substituted with an analytical sample at appropriate times, to react the analytical sample with a reaction reagent with which an element to be detected may develop colors so that the concentration of the element may be analyzed on the basis of the detection of the difference Δ in absorbance between the carrier and the analytical sample. More specifically, in FIA, a carrier and a reaction reagent are mixed and thoroughly stirred by means of agitation and dispersion before performing concentration detection (typically, measurement of absorbance on the basis of absorptiometry) using a detector for detecting element concentrations and, as such, by substituting the carrier with a sample at a time, the concentration of the sample is determined by measurement of the differential in absorbance. The disclosure of Japanese Unexamined Patent Publication (Kokai) No. 2004-163191 is to be incorporated herein by reference.
Patent Reference 1: Japanese Unexamined Patent Publication No. 2004-163191
Patent Reference 2: Japanese Patent Application No. 2004-321191